Ignition magneto



Oct. 12,1926. 1,602,474

- F. W. ANDREW IGNITION MAGNETO Original Filed Oct. 5. 1921 2 Shee ts-Sheet 1 XNVENTOR BY I ATTORNEY F. w. ANDREW IGNITION MAGNETO o i i l Filed 001.. 3. 1921 2 Sheets-Sheet 2 BY ORNEY Patented Oct. 12, 1926.

PATENT OFFICE.

UNITED STATES FREDERICK W. ANDREW, 0F GLEN HEAD, NEW YORK, ASSIGNOR T0 EISEMANN MAGNETO CORPORATION, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

IGNITION MAGNETO.

Original application filed October 3, 1921, Serial No. 504,934. Divided and this application filed April 10, 1924. Serial No. 705,462.

My invention relates to ignition magnetos, and its object is to provide a new and improved armature construction and circuitbreaker mechanism. The advantages of my invention will become apparent as the specification proceeds.

In the accompanying drawings;-

Fig. 1 is a longitudinal cross-section of a magneto embodying my invention;

Fig. 2 is a plan View of the magneto, certain parts being broken away for clearness to show the circuit-breaker contacts and mounting;

Fig. 3 is another plan view neto, with certain parts being broken away andothers in cross-section to show the cam that actuates the circuit-breaker;

Fig. 4 is an end view, approximately on line 4-4- of Fig. 1;

Fig. 5 is an enlarged view in cross-sew tion on line 5-5 of Fig. it, showing the short-circuiting device associated with the circuit-breaker;

Fig. 6 is a detached perspective view of the circuitbreaker mechanism;

Fig. 7 is a fragmentary perspective view showing how the movable circuit-breaker arm is grounded through a flexible conducting strip;

Fig. 8 is a detached perspective view of the cam which controls the movable arm of the circuit-breaker, this cam being for a onecylinder engine; and

Fig. 9 is a detached perspective view of a cam for a two-cylinder engine.

Since my present invention concerns itself only with circuit-breaker mechanism and associated parts, I need not describe in detail the structure of the magneto illustrated in the drawings. It will be suiiicient to point out that a rotary or oscillatory armature A is operatively mounted in the end walls of a non-magnetic frame or casting C carrying a permanent magnet or magnets M. The armature, carrying a primary Winding P and a secondary Winding S, is mounted to rotate or oscillate between the poles of magnet M to induce a high-tension current in the secondary winding, as Will be understood by those skilled. in the art. The armature has a pair of end disks or of the magplates 1 and 2 of non-magnetic material. These end plates, which are preferably of bronze or brass, are rigidly secured to the iron poles 3 of the armature core in any suitable way.

To the outer face of end plate 1 is secured a coliector ring 4, which may be made from a cut-punching of a suitable conducting material. The collector ring is insulated by a ring or washer 5 of insulating material, and is connected to a common lead or terminal of the primary and secondary windings, A collector brush 6 projects through the top 7 of casting G into contact with the collector ring. Thebrush 6 is connected to one terminal of a condenser K mounted in a recess or chamber 8 in the top of casting C, shown in Fig. 1.

The condenser chamber 8 is covered by a plate 9, which is held in place by screws 10 and 11. or by any other suitable means. As shown in Fig. 2, the plate 9 does not entirely cover the condenser chamber, but leaves space sufiicient to bring out the insulated condenser terminal 19.. The plate 9 has the advantage that it keeps the condenser compressed, thus insuring a practr cally constant capacity. To the terminal 12 are connected the brush 6 and conductor 13, while the other terminal of the condenser is grounded, these condenser connections being well understood by those familiar with ignition apparatus.

The conductor 13 is suitably connected to a fixed terminal 14st the point 15. The terminal M, which is a block of good conducting material, has an opening or slot 16 (see Fig. for receiving a rigid insulating strip 17. The terminal 14; .is secured at right angles to the insulating strip or bridge piece 17 by rivets 18, or otherwise. The strip 17 is made of an insulating material possessing sufficient rigidity and strength. such as bakelite canvas, and is mounted at its ends on a pair of posts 19 by screws 20, or otherwise. The posts 19 are preferably an integral part of the top 7 of the casting, as best shown in Fig 6. It will be seen that I have provided a very simple insulated mounting for the terminal 14, which is easily put in place and removed when required.

The terminal 14 carries an adjustable contact screw 21. which cooperates with a mo?- able contact 22 to form the circuit breaker of the magneto forcontrollingtheprimary cireuit. as will be understood by those skilled in the art. The movable contact 22 is carried at the outer end of the breaker arm 23. pivotcd to the casting by means ot a screw or pin 2i, which enters an opening in the top of casting C. The contact is normally pressed against the iiXed contact 21 by a s r-ring; coiled about the pin or screw 24:, as shown in Fig. 6. The fixed contact 21 is insulated and the movable contact 22 is grounded. As the movable pivot ot the breaker arm 23 acts like a high resistance contact, and as it is important in any hightension magneto to keep down the resistance 01" the primary circuit, I provide a flexible strip 26 of good conducting material for grounding the breaker arm 23. best shown in F 6 and 7, the strip 26 is at one end removably secured to the top 7 01' the casting by the screw 10. and at the other end is suitably connected to a lateral e21 tension 2? on the breaker arm 2 Preterably the connection between the breaker arm 23 and strip 26 is permanent. as a riveted or soldered joint. The strip 26, be ing easily flexible. does not. interfere with the movements of the breaker arm. The screw 10 clamps the strip 26 firmly between the top of the casting and the cover plate 0. The conductor 26 thus provides a fiXttl circuit connection of low resistance for the movable contact 22. The strip 26 which is very thin. is bent substantially at right angles to provide an arm of ellective length in a small space. and the connecting clip 27 is bent at right angles to the strip, to provide a flexible hinge for the entire strip dur ing; the operation of the breaker arm 23. in this way the strains of operation. instead of being localized, are distributed throughout the strip, thereby considerably proloncrinn' its life.

The breaker arm- 23 is formedwith a ri htangled extension 28, which carries at its Iree end a block 29 of suit-able wearing mate rial. such as fiber. The block is in verti cal al gnment with an actuating cam mounted on the end member 2 of the arniature. The form of this cam is best shown in Fin. where it is indicated as a whole by B. it will be seen taut the cam R consists of a disk or ring 30 having a section cutawa} at 31 and provided with a cylindrical flange The ends of the flange 32 are bevelled to form cam surfaces 33 and 34;. The cam ll, like the collector ring 4, is preferably made from a cut-punching. It will be undcrstood that the Form of cam R shown in Fig. is for a one-cylinder magneto and that the shape of the can. will naturally depend upon the number of cylinders in the engine to which the magneto is connected. he cam 1 id, which is preferably of hard steel. is secured to the end disk 2 of the armature by a screw 35, or otherwise Fig. \l'hcn the cam is in place on the disk 2, thetlaugc overlaps the periphery of the disk, as shownin Figs. 1 and Iucthcr words. the cam R "Forms in effect a removable section of the disk 2. v

It will be clear from Fig. 4. that. as long as the block 29 of" the breaker arm 23 engages the cylindrical flange 32- ot the cam It. the contacts 21 and 22 are hclo apart and the primary circuit of the n'iagneto is open. ll hen the block 29 rides over the peri ihery of disk 2. the circuit breaker is closed. the cam surface passes under the block 29 in the direction of the arrow (1. in Fig. the contacts are allowed to open under the action of spring 25 and they remain open until the opposite cam surface 3 1: rides under the block 2!) and rocks the breaker arm 23 into closed. position. During the interval. that the contacts 2l-22 remain closed, current 1215568 through the primary circuit P. The angular position of the circuit breakor cam R is such that it interrupts the primary circuit at approximately the moment of maximum voltage, thereby inducing a current of sulliciently high Voltage in the secondary circuit S to produce a spark. This operation is well understood and nothing further need be said about it.

To change the magneto from a right-hand to a left-b nd rotation, or ice vcisa. it is only nece ry to change the position 05 the cam R on the disk 2. For this purpose the disk 2 is provided with a pair of diametrically opposite screw holes 36. one of which is shown in Fig. 4; the other screw hole being covered by the screw The cam R is readily accessible upon ICll'lOVfll of the end plate or cover 37.

In ignition magnetos it is frequently desirable to short-circuit the primary coil in order to stop the ignition. I provide a short-circuiting device in an easily accessible position on the removable cover- 3S. which is fastened to the top oi casting (If bv screws 39, or otherwise. As best shown in the enlarged View of rig. 5, this device C0111- prises a contact pin 40, projeitiue" from a hollow plug 1-1. which ripjidl' cured to the cover 38 and insulated the c om by insulating washers 42 and 43. A; nut 44 holds the plug dl firmly in place on the covor A spring: to within the plug ll. pushes the pin it) against the terminal l i. The plug 41 has a screw-tln'eaded etztensitm on which is mounted a nut 47. It des .d, a spring 48 may l e placed around the screw 46 to hold the nut firmly in adjusted position. The not ell is thus electrically connected with the terminal Ll through pin 40, plug 41 and screw 46. As long as the nut 47 is out of contact with the grounded cover 38, the n'imary circuit is completed through the contra-ts 21 and :22 of the circuit breaker, as previously explained. However. when the nut 4.7 is screwet down until the i1 or rt at? thereof contacts with the ra shoulder 49 of the cover 38, the prim: B, current Sll()l.'lJ-Cll'01lli.6(I through pin 4-0, nut t? and the grounded cover 88.

If it is desired to control the short-circuiting device above described from a distant point, it is only necessary to clamp one end of a conductor between the nut 47 and the shoulder {1:9 in the cover; the other end of the conductor being fastened to a switch mounted on the dashboard or other part of the motor vehicle. The other terminal of the switch would, of course, be grounded. As long as the switch was open, the primary current would operate in the usual way, but upon closing the switchthe primary current would be short-circuitcd in the same way as above described. In using a shortcircuiting switch, it would not be necessary to use a Dlt with a flange or skirt like the nut 47, but an ordinary nut would be sufficient.

A onc-cylinder magneto constructed in accordance with my invention is readily changed into a multicylinder magneto by the substitution of a few parts. For the sake of explaining this feature of my invention, I will assume that a one-cylinder magneto is to be changed into a two-cylinder magneto. This is accomplished by simply ren'ioving the cam R and substituting a cam T, as shown in Fig. 9. The cam T is mounted on the end. plate 2 of the armature in the same way is the cam R. The cam T is provided with a pair of screw holes 50 arranged to register with the screw holes 36 in the disk 2, so that, by inserting screws into these aligned openings, the cam T is rigidly mounted on the disk 2 in a predetermined position. F or a two-cylinder magneto the cam T has two oppositely arranged camsections 51, since the circuit must be interrupted twice during every revolution of the armature.

. The distril'mtor D shown in the drawings is for a one-cylinder magneto and has, therefore, only a single contact 52 (see Fig. 3) in constant engagement with a conductor 52 mounted in the insulated portion 53 of the armature shaft and connected to the secondary winding. lVhen the cam T is substituted for cam R, the distributor D is replaced by a distributor having a pair of con tacts or brushes arranged to cooperate with a rotary contact on the armature shaft. It will not be necessary to show or describe the structural details of distributor D or the distributor-for a two-cylinder magneto, since these form no part of my present invention, because of an oilicial requirement of division in my copending application Serial Number Lia.

504,9?A, filed October 3, 1,921, of which the present case is a division. For the struc tural details of the distributors above mentioned, reference may be had to said copending application.

IVhile I have herein shown and described a specific construction, I do not intend to be limited to the details set forth. It is obvious that changes and modifications may be resorted to and yet be within the scope of my invention as defined in the appended claims.

hat I claim as my invention. is

1. In an ignition magneto, a rotatable armature having a pair of end plates, a cam mounted on one of said end plates and having a cylindrical flange overlapping an arc of the periphery of said end plate, C2111 means on said flange, and a circuit-breaker controlled by said cam means.

2. In an ignition magneto, a rotatable armature having a pair of end plates, a cam mounted on. one of said end plates, said cam consisting of a disk section and acylindrical flange extei'uiling from said disk section so as to overlie an arc of the peripl'icry of said end plate, cam means on said flange, fastening means passing tl'irough said disk section into said end plate, and a circnit-lneaker controlled by said cam means.

3. In an ignition magneto, a rotatable armature having a pair of end plates, a cam mounted on one of said end plates so as to be angularly adjustable thereon, and a circuit-breaker controlled by said cam.

4C. In an ignition magneto, a rotatable armature having a pair of end plates, a cam mounted on one of said end plates, said cam consisting of a dish section and a cylindrical flange extending from said disk section so to overlie an arc of the periphery of said end plate, cam means on said flange, said flange and its cam means being so constructed that said cam may be mounted on. said end plate in reverse positions dependi upon the direction of rotation of the magneto sl aft, fastening means pas..'ng thror ,.;h said disk section into said end plate, said fastening means permitting the mounting of said cam on said end plate in either position, and a circuit-breaker controlled by said cam means.

5. As a new article of manufacture for use in ignition magnetos, a circuit-breaker cam made from a one-piece cut-punching consisting of a. disk section and a cylindrical flange extending axially from said disk sec tion, an arc of said flange being cut away and the ends of said flange being bevelled to provide cam surfaces.

6. In an ignition magneto, a nonmagnetic frame having a top, an armature journalled in said frame, a circuit-breaker mounted on said top, and a cam carried by said armature for actuating said circuitbreaker, said armature and cam being removable from said frame without disturl ing said circuit-breaker.

7. As a new article of manufacture for use in ignition magnetos, a circuit breaker cam made of a one-piece cut-punching consisting of a disk portion from the periphery of which extends axially a circular flange provided with a cam surface, substantially as and for the purpose specified.

S. In an ignition magneto, a non-magnet ic frame in which the armature is journalled, said frame having a top, an insulating bridge piece mounted on said top near one end thereof, a terminal block rigidly secured to said insulating bridge pieces between the ends thereof and connected in the armature circuit, a screw carried by said terminal, a spring-pressed arm pivoted in the top of said frame and having a contact normally engaging said screw, and means for operating said pivoted arm.

9. As a new article of manufacture for use in ignition niagnelios, a stationary contact for a circuit breaker, said contact consisting of a block having a slot or recess at one end and a contact member at the other end, substantially as and for the purpose specified.

10. As a new article of manufacture for use in ignition inagnetos, a stationary contact for a circuit-breaker, said contact comprising a block with a slot or recess at one end and a contact member at the other end, and a rigid strip of insulated material tirinly fitted in said slot or recess. whereby said strip extends substantially at right angles to said block and acts as insulating support therefor.

11.111 an ignition magneto, a circuitbreaker comprising an insulated stationary contact, a spring-pressed pivoted arm carrying a contact normally held against said stationary contact, and a flexible conductor connected at one end to said arm and at the other end grounded to the magneto frame.

12. In an ignition magneto, a circuitbreaker comprising an insulated stationary contact, a spring-pressed pivoted arm carrying a contact normally held against said stationary contact, and a thin flexible strip of conducting material permanently connected at one end to said arm and reinovably connected at the other end to the magneto frame.

13, In an ignition magneto, a non-magnetic frame having a top a circuit breaker having a fixed terminal block mounted on said top. a grounded cover for said top, and an adjustable sliort-circuiting device on said cover, said device having an insulated metalpart adapted to extend permanently into contact with said terminal block, and an adjustable member on said device for ground ing said part to the cover.

14:. As a new article of manufacture for use in inagnetos, an electrical conductor consisting of a thinv flexible strip of metal having a body portion bent transversely at substantially right angler, one end of said body portion having a perforated lug bent along the edge of the liody portion substantially at right an les to the plane of the body portion at ad end. substantially as and for the purpose specified.

15. In an ignition magneto, a circuitbreaker comprising an insulated stationary contact a spring-pressed pivoted arm carrying a contact normally held against said stationary contact. thin flexible strip of conducting material bent transversely at substantially right angles intermediate its ends. one end of said s 'ip being f "'tened to said arm and the other end having a lug bent along the edge of the strip at right angles to the plane of the strip at that end, and a removable fastening Tiltll'lllCi for connecting said lug to the frame of the magneto. 7'

16. In an ignition magneto, a rotatable armature having end plates, a circuit breaker cam made from a cut-punching and consisting of a llat circular disk section and a plurality of cylindrical flanges extending axially from said disk section and spaced from each other, and means for securing said disk section against the face of one of said armature plates, so that said flanges overlie the periphery of said end plate, the ends of said flanges being bevelled to provide cam surfaces.

FREDERICK XV. ANDRE- 

